ABSTRACT Hyperoxaluria, defined as the presence of excess oxalic acid and/or oxalate salts in urinary excretions, is a physiological condition associated with an increasing number of common and debilitating chronic diseases whose prevalences are increasing in both the United States and the rest of the world. Oxalic acid is a natural and abundant by-product of metabolism, but also a highly oxidized organic compound with powerful chelating activity that, in high concentrations, can cause death in both animals and humans due to its corrosive effects. More commonly, however, hyperoxaluria is now associated (or correlated) with a variety of pathological disorders, including cardiomyopathy, cardiac conductance disorders, urolithiasis, fungal infections, cystic fibrosis, colitis, primary hyperoxaluria type-I, pyridoxine deficiency, and steatorrhea. Thus, regulating oxalate levels in the body is receiving greater recognition as an important factor in controlling the effects of hyperoxaluria in multiple pathologies. Unfortunately, current testing for hyperoxaluria is expensive, time- consuming and mainly conducted by trained technicians in well-equipped laboratories. This SBIR proposal addresses a serious issue in the field of hyperoxaluria-associated pathologies: the lack of a simple, rapid point- of-care device to monitor oxalate levels in biological fluids. To address this deficiency, we propose to complete the development of a dipstick test that rapidly and accurately measures oxalate levels in urine. To obtain proof- of-concept, the team proposes the following Phase I Specific Aims: 1) Develop a dipstick test from which results can be obtained by visual reading, and 2) Perform in-vitro testing of the dipsticks to determine the sensitivity, specificity, accuracy, and reproducibility. Development of a dipstick for quantifying changes in oxalate levels, similar to the glucometer for measuring glucose levels, would represent a unique advancement for patients suffering with diseases ranging from calcium-oxalate kidney stone disease to cystic fibrosis and primary hyperoxaluria type 1. Our preliminary data suggest the stated aims will be readily achieved. Once proof-of-concept is confirmed, the team will move into Phase II, which will focus on clinical functionality and performance of the dipstick.